Effect of angularly annelated strained rings on benzene: structures of 1,2-dihydrocyclobuta[a]cyclopropa[c]-, 1,2,3,4-tetrahydrodicyclobuta[a,c]- 1,2,3,4-tetrahydrodicyclo[a,c]cyclopropa[e]-, and 1,2,3,4,5,6-hexahydridotricyclobuta[a,c,e]benzene in the crystal.
; Blaeser, Dieter; Billups, W. Edward; Haley, Michael M.; Maulitz, Andreas H.; Mohler, Debra L.; Vollhardt, K. Peter C.
Angewandte Chemie, Jg. 106 ; Heft 3, S. 321 - 325
The crystal structures of small annelated benzene derivs., benzocyclopropene and benzocyclobutene derivs., were detd. Alternating bond length were found to be insignificant (<0.025 .ANG.); it was concluded that the benzene ring maintains arom. behavior even if the s-structure is disturbed. The high-temp. phase and low-temp. phase structures of tricyclobutabenzene (I) were discussed.